Now that developers have scrapped a plan to build a golf course and three sports fields at Bayfront Park, city officials are debating how to create those fields on their own.

Highlands Golf retracted its bid last month to build an 18-hole golf course at the park, which consists of 160 acres of open space. As part of that proposal, Highlands would have built three new regulation-size sports fields. Menlo Park currently has nine fields, but none of them are full-sized.

Now, it’s up to the city to determine whether — and where — it can build new fields, which officials say are badly needed. Tonight, City Manager Dave Boesch and the City Council will launch talks on that process, which will continue April 25.

With the Highlands proposal, “We were talking about two adult-sized soccer fields and one adult-sized softball field,” with synthetic turf and field lights, according to City Councilmember Lee Duboc.

Those fields could take up to six acres of park space, including restrooms, outbuildings and parking, and cost about $1 million each, Duboc said. Highlands would have paid that cost — and operations at the golf course would have netted the city as much as $200,000 a year, according to Boesch.

Creating athletic fields on Bayfront Park, which is built on landfill over Bay mud, may have hidden costs, according to Robin Smith, a conservationist with the Audubon Society. “Since the ground moves, the fields would not stay flat and you have to keep working on them,” Smith said. “It would be a real drain on city finances.”

The plan would also require changes to the city’s general plan and its permit with the Bay Conservation and Development Commission.

Highlands pulled its proposal after facing hefty opposition from the Friends of Bayfront Park and other groups interested in preserving Bayfront Park as open space. “They ultimately decided there was too much risk of being unsuccessful in obtaining the requisite permits and community support,” Boesch said.

Audubon Society members worry that developing the park or adding lights would interfere with bird habitat and migration patterns, according to Smith.

The Menlo Park City Council will discuss the future of Bayfront Park tonight at 7 p.m. at City Hall, 701 Laurel St.